This invention relates to high pressure discharge lamps.
High pressure discharge lamps include a discharge vessel having a closure with an aperture therethrough, an electrode lead-through extending through the aperture, and an electrode rod mounted on the lead-through and inserted within the discharge vessel.
During at least one commercially viable manufacturing process for a discharge lamp, the lead-through is scraped at a location on its outer surface. Ideally, the lead-through is evenly scraped, then inserted into the aperture until its scrape contacts the closure, so it is mounted perpendicularly at a predetermined height in the discharge vessel. The scrape on the lead-through limits the extent of insertion of the lead-through into the discharge vessel, and determines the distance its electrode rod is inserted within the discharge vessel.
High pressure discharge lamps manufactured in this fashion can have the scrape on the lead-through be made irregular or uneven. Because the uneven scrape on the lead-through will unevenly contact the closure, the lead-through will not mount perpendicularly on the closure with a centerline attitude, but instead mount at an angle. Or alternatively, it will not mount at all and instead push through and fall into the discharge vessel. Consequently, the uneven scrape on the lead-through can cause the discharge lamp to have a substantially shorter lamp life or defective lamp operating characteristics.
In another high pressure discharge lamp of this type, an electrode rod is supported by a tubular in-lead. The tubular in-lead has a bidirectional crimp functioning only to retain or lock the electrode rod within the tubular in-lead.